Prosecutors increasingly turn to expert witnesses in their effort to prove that an accuser is telling the truth. Yet experts are not lie detectors. Psychologists and people who purport to be skilled at reading microexpressions might or might not be better than ordinary jurors at determining whether someone is lying, but even polygraph evidence is inadmissible in court. It is the function of the jury, not a witness, to decide whether an accuser is telling the truth.
The Michigan Supreme Court recently decided two consolidated cases that address experts who essentially vouch for the credibility of children who testify that they were sexually assaulted. This post addresses a doctor who diagnosed a child as a probable victim of sexual abuse based solely on the child’s statements to the doctor. A separate ExpertPages post addresses a social worker who testified about his unsupported opinion that children “overwhelmingly” do not lie about being sexually abused.
Facts of the Case
A girl identified as TH was raised in a dysfunctional home by a drug-addicted mother before being placed in foster care. While she was living with her mother, TH’s uncle, Brandon Harbison, occasionally babysat for TH. Harbison was 18 and TH was 9.
While watching a movie with her foster mother, TH claimed that Harbison had done something “really bad” to her. TH was interviewed by a social worker and a pediatrician, among others. After she alleged that Harbison touched her in a sexual way, Harbison was arrested and charged with a number of sex offenses.
TH testified that she was sexually abused at least 30 times, at least once while her older brother was in the room. She testified that Harbison made her watch pornography, attempted vaginal and anal penetration, and placed his penis in her mouth.
No witness corroborated TH’s testimony. During part of the time that TH claimed Harbison was sexually abusing her, Harbison was in jail because of a probation violation.
TH’s grandmother testified that TH was never alone with Harbison when he babysat TH at the grandmother’s house. Harbison’s girlfriend testified that she was always with Harbison when he babysat at TH’s residence and that Harbison was never alone with TH.
After Harbison was convicted, new counsel persuaded the trial court that Harbison’s trial lawyer was ineffective because he failed to present the testimony of TH’s brother, who would have denied that Harbison had sexual contact with TH in his presence. Remarkably, the Michigan Court of Appeals reversed the trial court’s decision to grant Harbison a new trial.
The appellate court thought that TH’s brother had “credibility problems” and that the jury might not have believed him. Of course, if the jury believed TH’s brother, it might have decided that TH’s obvious credibility problems created a reasonable doubt about Harbison’s guilt. Since the jury never heard the brother testify, it is impossible to know whether the testimony would have changed the trial’s outcome.
The prosecution called Dr. N. Debra Simms as an expert witness. Dr. Simms is a pediatrician who testified as an expert in the field of “child sexual abuse diagnostics.”
Dr. Simms conducted a head-to-toe physical examination of TH. She found no physical evidence that TH had been sexually abused. TH’s hymen was intact and her genitalia showed no trauma that could be attributed to sexual abuse.
Dr. Simms nevertheless testified that she diagnosed TH as a probable victim of pediatric sexual abuse. She based the diagnosis on information she received from TH and from the foster mother.
Dr. Simms also testified that she based her diagnosis on a “practice standard” developed by “individuals that do pediatric sexual abuse evaluation nationwide.” In her view, the standard calls for a diagnosis of probable pediatric sexual abuse if the alleged victim tells a consistent story of sexual abuse to the pediatrician, even if the pediatrician’s physician examination reveals no evidence that would corroborate the story.
Michigan Supreme Court Decision
The Michigan Court of Appeals concluded that Dr. Simms was entitled to take TH at her word and that her expert testimony was therefore admissible. To the extent that it was error to admit her testimony, the appellate court concluded that the error was not prejudicial because TH testified and the jury was able to evaluate her credibility independently of Dr. Simms’ testimony.
Unsurprisingly, the state supreme court found that the court of appeals had ignored Michigan precedent. Michigan has long recognized that a pediatrician’s expertise does not extend to knowing whether a patient is being truthful.
A pediatrician can make findings based on a physical examination and can base a diagnosis on those findings. The patient’s statement might help a pediatrician arrive at a diagnosis — if there are alternate explanations for a physical finding, the patient’s explanation might guide the diagnosis — but in the absence of physical evidence, a physician’s diagnosis that a patient was sexually abused rests on nothing more than the pediatrician’s unsupported belief that the patient is telling the truth.
Notwithstanding that precedent, the Michigan Supreme Court cited six instances in which the Michigan Court of Appeals concluded that an examining physician’s diagnosis of “probable pediatric sexual abuse” was erroneously admitted. Some of Michigan’s trial judges apparently didn’t the message that the supreme court long ago sent, leading to multiple convictions based in part on inadmissible testimony.
The Michigan Supreme Court concluded that Dr. Simms’ testimony was prejudicial. The jury could only have viewed Dr. Simms as vouching for TH’s credibility. The trial was a credibility contest and TH’s credibility was suspect. The prosecution called Dr. Simms as a witness in the likely belief that the jury would regard her testimony as bolstering TH’s credibility. Dr. Simms’ testimony was prejudicial because it invaded the jury’s role in assessing the credibility of accusers.
The court also faulted Dr. Simms for claiming that her diagnosis was based on a “national standard” when the authors of the article she cited made clear that pediatricians should not rely on the article to make a diagnosis of “probable pediatric sexual abuse” at trial. The standard relates to a pediatrician’s duty to report suspected abuse, not to a pediatrician’s trial testimony. The authors forthrightly acknowledged that in the absence of physical evidence, pediatricians have no way of knowing whether a child is telling the truth, and that convictions may be unreliable if they are based on a medical opinion that is not supported by medical evidence.
No reasonable person thinks that a person who sexually abuses a child should avoid a conviction. But our time-honored system of justice attempts to assure that only the guilty are convicted and punished. To achieve that goal, the Constitution demands that individuals accused of crime — all crimes, no matter how much sympathy we might feel for the alleged victim — receive a fair trial.
Courts have long understood that only a jury can determine whether an accuser is telling the truth. Juries cannot be assisted in that chore by witnesses who testify that they believe the alleged victim. Vouching for the alleged victim’s credibility is particularly likely to result in an unfair trial when a witness with a respected position, and particularly a witness who is identified as an expert, testifies or implies that the alleged victim is telling the truth.
Yet vouching by social workers, psychologists, pediatricians, and other expert witnesses has become commonplace in child abuse trials. Defense attorneys must be prepared to object and to cite decisions like Harbison when a prosecutor asks an expert to state an opinion that implies the expert’s belief that the accuser is telling the truth.
At the same time, experts must understand that they do not take the witness stand as advocates for children but as impartial reporters of opinions that they base on sound methodologies. An advocate’s opinion that a child’s accusation should always be believed is not the kind of methodology that can reasonably inform an ethical expert’s opinion.